Sox9 Deletion Causes Severe Intervertebral Disc Degeneration Characterized by Apoptosis, Matrix Remodeling, and Compartment-Specific Transcriptomic Changes

Transcriptomic analysis of nucleus pulposus (NP) and annulus fibrosus (AF) tissues from intervertebral discs of 3-month-old mice with the conditional postnatal deletion of Sox9. The transcription factor Sox9 is essential for the maintenance and health of the intervertebral disc of mice. We examined the transcriptomic profiles of nucleus pulposus and annulus fibrosus cells in control and Sox9 conditional knock-out mice using microarrays. Tissues from the nucleus pulposus (NP) and annulus fibrosus (AF) were harvested from the intervertebral discs of four Sox9 control (Sox9CTR) (Sox9fl/fl) and four Sox9 conditional knock-out mice (Sox9cKO) (AcanCreERT2Sox9fl/fl) between 3 and 4 months of age. NP and AF tissues were separately pooled from lumbar and caudal discs in each animal for RNA extraction and hybridization using Affymetrix microarrays.